Title: Muon g - 2 in the aligned two Higgs doublet model

In this paper, we study the Two-Higgs-Doublet Model with the aligned Yukawa sector (A2HDM) in light of the observed excess measured in the muon anomalous magnetic moment. We take into account the existing theoretical and experimental constraints with up-to-date values and demonstrate that a phenomenologically interesting region of parameter space exists. With a detailed parameter scan, we show a much larger region of viable parameter space in this model beyond the limiting case Type X 2HDM as obtained before. It features the existence of light scalar states with masses 3 GeV ≲ m H ≲ 50 GeV, or 10 GeV ≲ m A ≲ 130 GeV, with enhanced couplings to tau leptons. The charged Higgs boson is typically heavier, with 200 GeV ≲ m H+ ≲ 630 GeV. The surviving parameter space is forced into the CP-conserving limit by EDM constraints. Some Standard Model observables may be significantly modified, including a possible new decay mode of the SMlike Higgs boson to four taus. Lastly, we comment on future measurements and direct searches for those effects at the LHC as tests of the model.

@article{osti_1327255,
title = {Muon g - 2 in the aligned two Higgs doublet model},
author = {Han, Tao and Kang, Sin Kyu and Sayre, Joshua},
abstractNote = {In this paper, we study the Two-Higgs-Doublet Model with the aligned Yukawa sector (A2HDM) in light of the observed excess measured in the muon anomalous magnetic moment. We take into account the existing theoretical and experimental constraints with up-to-date values and demonstrate that a phenomenologically interesting region of parameter space exists. With a detailed parameter scan, we show a much larger region of viable parameter space in this model beyond the limiting case Type X 2HDM as obtained before. It features the existence of light scalar states with masses 3 GeV ≲ mH ≲ 50 GeV, or 10 GeV ≲ mA ≲ 130 GeV, with enhanced couplings to tau leptons. The charged Higgs boson is typically heavier, with 200 GeV ≲ mH+ ≲ 630 GeV. The surviving parameter space is forced into the CP-conserving limit by EDM constraints. Some Standard Model observables may be significantly modified, including a possible new decay mode of the SMlike Higgs boson to four taus. Lastly, we comment on future measurements and direct searches for those effects at the LHC as tests of the model.},
doi = {10.1007/JHEP02(2016)097},
journal = {Journal of High Energy Physics (Online)},
number = 2,
volume = 2016,
place = {United States},
year = {2016},
month = {2}
}

In models with extended Higgs sector and additional matter fields, the decay modes of heavy Higgs bosons can be dominated by cascade decays through the new fermions rendering present search strategies ineffective. Here, we investigate new decay topologies of heavy neutral Higgses in two Higgs doublet model with vectorlike leptons. We also discus constraints from existing searches and discovery prospects. Among the most interesting signatures are monojet, mono Z, mono Higgs, and Z and Higgs bosons produced with a pair of charged leptons.

Constraints on the general two Higgs doublet model ({open_quotes}model II{close_quotes}) are obtained from the existing (g{minus}2){sub {mu}} data including limits on Higgs boson masses from CERN LEP I data. We consider two scenarios: with a light scalar h and with a light pseudoscalar A, assuming M{sub h}+M{sub A}{ge}M{sub Z} (the charged Higgs boson contribution is also included). We evaluate separately the 95{percent} C.L. bands for positive and for negative contributions, relevant for a light scalar and a light pseudoscalar scenario, respectively. It is found that already the present (g{minus}2){sub {mu}} data improve limits obtained recently by the ALEPH Collaboration onmore » tan{beta} for the mass of the pseudoscalar below {approx_lt}2 GeV. The improvement in the accuracy by a factor of 20 in the forthcoming E821 experiment may lead to more stringent limits than provided by the ALEPH group, up to M{sub A}{approximately}30 GeV if the mass difference between h and A is {approximately}M{sub Z}. Similar results should hold for a light scalar scenario as well. {copyright} {ital 1997} {ital The American Physical Society}« less

The simplest extension of the Two Higgs Doublet Model is the addition of a real scalar singlet, S. The effects of mixing between the singlet and the doublets can be manifested in two ways. It can modify the couplings of the 126 GeV Higgs boson, h, and it can lead to direct detection of the heavy Higgs at the LHC. In this paper, we show that in the type-I Model, for heavy Higgs masses in the 200-600 GeV range, the latter effect will be detected earlier than the former for most of parameter space. Should no such Higgs be discoveredmore » in this mass range, then the upper limit on the mixing will be sufficiently strong such that there will be no significant effects on the couplings of the h for most of parameter space. Thus, the reverse is true in the type-II model, the limits from measurements of the couplings of the h will dominate over the limits from non-observation of the heavy Higgs.« less

In this paper, we study a two Higgs doublet model extended by vectorlike leptons mixing with one family of standard model leptons. Generated flavor violating couplings between heavy and light leptons can dramatically alter the decay patterns of heavier Higgs bosons. We focus on pp → H → ν 4ν μ → W μν μ, where ν 4 is a new neutral lepton, and study possible effects of this process on the measurements of pp → W W and H → W W since it leads to the same final states. We discuss predictions for contributions to pp → Wmore » W and H →WW and their correlations from the region of the parameter space that satisfies all available constraints including precision electroweak observables and from pair production of vectorlike leptons. Large contributions, close to current limits, favor small tan β region of the parameter space. We find that, as a result of adopted cuts in experimental analyses, the contribution to pp → W W can be an order of magnitude larger than the contribution to H → W W . Thus, future precise measurements of pp → W W will further constrain the parameters of the model. Also, we also consider possible contributions to pp → W W from the heavy Higgs decays into a new charged lepton e 4 (H → e 4μ → W μν μ), exotic SM Higgs decays, and pair production of vectorlike leptons.« less

We introduce a strategy to study the parameter space of the general, CP-conserving, two-Higgs-doublet Model (2HDM) with a softly brokenmore » $$\mathbb Z_{2}$$-symmetry by means of a new “hybrid” basis. In this basis the input parameters are the measured values of the mass of the observed Standard Model (SM)-like Higgs boson and its coupling strength to vector boson pairs, the mass of the second CP-even Higgs boson, the ratio of neutral Higgs vacuum expectation values, and three additional dimensionless parameters. Here, using the hybrid basis, we present numerical scans of the 2HDM parameter space where we survey available parameter regions and analyze model constraints. From these results, we define a number of benchmark scenarios that capture different aspects of non-standard Higgs phenomenology that are of interest for future LHC Higgs searches.« less